Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Polymer optical fibres for rough environment and sensor applications

The project was directed towards the development of polymer optical fibre (POF) sensors for the detection of alkali, earth-alkali and heavy-metal ions. The research activity consisted of two parts: design of a sensor element transducing chemical recognition into an optical signal and; preparation of polymer waveguides to transfer the chemical information over short distances. The research activity of the third year has been focused on optimalization of the ion transport properties. For this purpose, a series of benzo-15-crown-5 and calix[4]arene substituted poly(siloxane) and carbon monoxide/alpha-olefin copolymers was synthesised. Optimization was performed in terms of the following variables: type of receptor molecule, polymer content of the receptor moieties, length of the spacer. Polymer supported membranes were prepared to measure permeability and selectivity of alkali metal ions. A threshold concentration was detected above which the ion transport is drastically enhanced due to the formation of percolating arrays of the receptor moieties. Selectivity of the membranes with respect to sodium ions potassium ion and lithium ions was controlled by varying receptor molecules. Special attention has been paid to long term stability of the performance properties of the membranes. Superior stability was achieved due to the chemical bonding of receptor moieties to the polymer backbone. Temperature resistant POFs were prepared based on copolymers of 1-adamantylmethacrylate (AdMA) and methylmathacrylate. The spinning process was developed with an optical fibre producer. In addition to the main research activity, two concepts (gel-template-leaching-membranes and degradable dendritic molecules) have been combined to prepared nanoporous membranes with well defined size and chemical structure of the pores. This part of the project needs further investigation to control the pore size and recognition properties of such membranes.